Ken, companies do not have to disclose to the public every little chemical they put into their plastic formulations, and even polyethylene often has some kind of plasticizers.
What are plasticizers? They are chemicals that help to make the plastic, well more plastic and pliable/flexible. A harder HDPE type plastic is going to have less (or no) plasticizers in it than say a ziplock or grocery bag. They do not necessarily have to be hormone mimicking and disrupting in nature, but as we learn more, it seems like a definite percentage have those kinds of effects, and sometimes worse than BPA.
I don’t know if it’s used in modern plastics, but there is an old, natural plasticizer that many of us know of as glycerin, which use to be a byproduct of soap making. This is very safe for the body, and can be, and is often eaten/put in foods.
I’ve experimented with using glycerin in creating gel electrolyte battery formulations. Interesting stuff. Unfortunately, it has a tendency to attract water/moisture to it. It would be cool if it could be added to PE to soften/plasticize it some.